Designing the experiment set-up

How do you contain a ferrofluid in microgravity so that it does not move around unpredictably? What kind of magnetic field do you need to do this, and how can you achieve it? How do you prevent the ferrofluid from coating the walls of its container, and how do you set up a detection system that fully captures the behaviour of the ferrofluid? These questions are crucial for designing our experiment set-up.

Another blog about our microgravity experiment! This time, I will tell you a bit more about our experiment and the design of our set-up, which we are working very hard on at the moment. The first version of our experiment report is due in May. The experiment report is our working document in which we work out all the aspects of our project. The design of the experiment set-up is an important part of it. Without a design, there is no experiment. To quickly refresh your memory, our experiment is about the movement of ferrofluids in microgravity under the influence of a magnetic field as a function of a certain actuation. This objective immediately raises a number of questions about the set-up. How can we contain the ferrofluid so that it does not move around unpredictably in the drop capsule? What kind of magnetic field do we need to control the ferrofluid, and how can we create it? Are there any obstacles to detecting ferrofluids, and how do you achieve the actuation of the ferrofluid container?

EMG 700 water-based ferrofluid.

Over the course of my study, I've gained a fair idea of how to tackle these types of design questions. For example, it is useful to break down the experiment set-up into smaller subsystems. We did this for ESA Drop Your Thesis, coming up with a bunch of requirements for the main subsystems. This really helped us to identify the important design challenges. For example, ferrofluids are grey and opaque fluids. If the ferrofluid coats the wall of a container and obstructs the view, any filmed images will be useless. It might therefore be smart to pick a water-based ferrofluid rather than an oil-based one, and to coat parts of the inside of the container with a hydrophobic material.

Plexiglass containers

What's new for me in this project is that, besides finding solutions for the design challenges that we face, we have to think about where to buy the materials we need, and how to get the funds to do so. There's a lot more to a project like this than just the engineering. It's a more practice-based situation than most university projects, and I'm definitely learning a lot from it. However, it also makes the design process a whole lot more complicated. Despite this, we have been able to make quite a lot of progress with the design. We've even already laid our hands on some hardware! For example, we've bought: two types of ferrofluids which we'll use for testing and the actual campaign; a plexiglass cylinder that we'll use to build the container; and wooden panels to test the lighting conditions and detection in the capsule. I must say, it's pretty satisfying to see your own project taking shape like that!

Tim Hermans, a master's student in space exploration, participates in the 'Drop Your Thesis!' programme at the European Space Agency. This is a hands-on student project in which an experiment will be designed and carried out in microgravity in the ZARM Drop Tower in Bremen, Germany. The exciting but challenging programme requires hard work and careful management and planning. The coming year, Tim will post monthly blogs every last Friday of the month about his experiences and the ups and downs of his project. You can follow Tim's project team on Facebook as well.